FIG. 1 is a simplified block diagram of a prior-art SNMPv3 network 10 including a Network Management System (NMS) node, device or apparatus 12 interconnected by data paths designated generally as 14 with a plurality of managed devices 16a, 16b, and 16c of a set 16 of managed devices. In FIG. 1, the various managed devices of set 16 include sensors, designated 16 as, 16bs, . . . , 16cs for measuring one or more physical parameters of equipment associated with the managed devices. Such a sensor might be, for example, a temperature-sensitive analog device together with an analog-to-digital converter (ADC) for converting the analog information into digital form. The user 18 interacts, typically by means of a graphical user interface (GUI) computer program with the NMS node, device or apparatus 12, for issuing commands as to how the NMS node 12 is to interact with the various managed devices.
The network of FIG. 1 uses Simple Network Management Protocol (SNMP) for managing the auxiliary or managed devices of set 16 of FIG. 1, and more particularly uses the most secure of the three versions of the SNMP protocol, which is SNMPv3. Simple Network Management Protocol (SNMP) v3 has an option for encrypting the user information flowing between or among the user GUI 18, the NMS 12, and the various managed devices of set 16. Encryption of the user information is termed “authentication” encryption or an authentication “password.” Simple Network Management Protocol (SNMP) v3 also has an option for encrypting the SNMP message itself, which is referred to as a “privacy” encryption or password. Both the authentication and privacy passwords must be included in the SNMP message, and the passwords used by the NMS 12 and the user devices of set 16 must match in order for the message to be acted upon by the managed device.
FIG. 2 is a simplified functional block diagram of a prior-art network including a Network Management System (NMS) node device 12, and also including a managed device of set 16 of FIG. 1, taken for definiteness as being managed device 16b. Managed device 16b is also referred to as “Device 2.” In FIG. 2, a request from the user's interface GUI is applied to a block 201a of NMS node 12, which regenerates the request in locally acceptable format. The local request is coupled from block 201a to a block 201b, which represents comparison of the credentials accompanying the request with locally stored versions for verification. The credentials are typically authorization and privacy passwords. In FIG. 2, internal request block 201a of NMS 12 receives from the user 18, by way of the GUI and a port 201ap, a request for information from Device 2. Block 201a generates an internal request. The internal request is applied to a block 201b to look up the current authentication and privacy passwords. The passwords found in block 201b are used in a block 201c to create an encrypted command. Then the encrypted command is sent out to a network, as represented by block 201d and a network path P. Device 2 receives the command at a block 202a by way of path P. Block 202b decrypts the encrypted command by the use of passwords previously stored in Device 2. The decrypted command is sent from block 202b to response generation block 202c. Block 202c gets local sensor information and generates a response. The response or status is then sent to the network, as represented by block 202d. 
FIG. 3 is a simplified logic or control flow chart or diagram of the prior-art steps required in the prior-art network management system apparatus 10 of FIG. 1 in order to request information relating to a sensor. In FIG. 3, the user logs into NMS GUI, as indicated by block 203a. The user identifies the information that is desired, and then manually selects the new passwords to be used in authentication process, as suggested by block 203b. The user initiates a START command to command NMS 12 to send the newly selected passwords to all the remote managed devices of set 16, as suggested by block 203c. Block 203d represents the encoding of the new passwords using the old or previous passwords, and the sending of encoded new passwords to the various managed devices. Block 203e represents the receipt by the NMS node 12 of acknowledgement signals from the managed devices of set 16, encoded with the new passwords. The NMS node 12 polls for the requested information as in the prior art, as suggested by block 203f. If the user has additional requests, he returns to the first step, 203a, as suggested by the NO output of decision block 203i. If the requests have been completed, the user logs off the NMS system, as suggested by the YES output of decision block 203i and by block 203g. At some later time, the user has to go thru the same process again, as suggested by block 203h. 